In certain circumstances, it is desirable to inject medication directly into human tissue. Typically, syringes or pen injection devices are used to inject medicaments into tissue areas, such as the intramuscular tissue layer, the subcutaneous tissue layer, and the intradermal tissue layer.
The assembly and operation of a typical pen injection device is described in commonly-assigned U.S. Pat. No. 7,645,264, which is hereby incorporated by reference in its entirety.
Pen injection devices, such as an exemplary pen injector 100, as shown in FIGS. 1 and 2, typically comprise a dose knob/button 24, an outer sleeve 13, and a cap 21. The dose knob/button 24 allows a user to set the dosage of medication to be injected. The outer sleeve 13 is gripped by the user when injecting medication. The cap 21 is employed by the user to securely hold the pen injector 100 in a shirt pocket, purse, or other suitable location.
FIG. 1B is an exploded view of an exemplary drug delivery pen shown in FIG. 1A. The dose knob/button 24 has a dual purpose and is used to both set the dosage of the medication to be injected and to inject the dosed medicament via the lead screw 7 and stopper 15 through the medicament cartridge 12, which is attached to the drug delivery pen through a lower housing 17. In standard drug delivery pens, the dosing and delivery mechanisms are all found within the outer sleeve 13 and are not described in greater detail herein as they are understood by those knowledgeable of the prior art. The distal movement of the plunger or stopper 15 within the medicament cartridge 12 causes medication to be forced into the needle 11 of the hub 20. The medicament cartridge 12 is sealed by septum 16, which is punctured by a septum penetrating needle cannula 18 located within the hub 20. The hub 20 is preferably screwed onto the lower housing 17, although other attachment means can be used such as attaching to the cartridge. To protect a user, or anyone who handles the pen injection device 100, an outer cover 69, which attaches to the hub 20, covers the hub. An inner shield 59 covers the patient needle 11 within the outer cover 69. The inner shield 59 can be secured to the hub 20 to cover the patient needle 11 by any suitable means, such as an interference fit or a snap fit. The outer cover 69 and inner shield 59 are removed prior to use. The cap 21 fits snugly against outer sleeve 13 to allow a user to securely carry the drug delivery pen 100.
A pen needle, which includes the hub 20, needle 11, outer shield 69 and inner shield 59, is typically used for a single injection and is then disposed of. Accordingly, patients must carry several pen needles to perform multiple injections over a period of time. Pen needles are generally stored loose in a container so that there is no simple and convenient way for a patient to keep multiple pen needles together. Accordingly, a need exists for a user to easily and conveniently carry a plurality of cannulas for use with a drug delivery pen.
Pen needles are usually sold individually packaged inside a plastic cover (such as outer shield 69) with a label (not shown) covering the opening in the cover to provide a sterility barrier. To use the pen needle assembly 10, the user removes a sterile cover (not shown) on the outer shield 69, twists the hub 20 onto the lower housing 17, removes the outer shield 69, and then finally removes the inner shield 59. Accordingly, the user must remove needle hub packaging, including the inner and outer shields 59 and 69, to connect a pen needle to a drug delivery pen to ready the device for an injection. This process must be repeated for each successive injection, in addition to properly disposing of the pen needle used for the previous injection.
Accordingly, a need exists for a storage assembly that stores a plurality of cannulas before and after their use. A need also exists for such a storage assembly that dispenses a cannula when actuated by a user and connects the dispensed cannula to the drug delivery pen.
Existing multi-needle injection devices are typically of two configurations. The first configuration retains the cannulas in a flexible bandolier, e.g, a bullet bandolier. The bandolier or cannula is then incrementally fed to the injection axis. The second configuration retains the cannulas in a magazine or cartridge. Either the magazine is incrementally moved to align a cannula with the injection axis, or a cannula is removed and transferred to the injection axis. Both configurations reduce the size of the design envelope of the pen needle from the traditional single-use design envelope. However, both configurations still incorporate a needle hub, which increases the volumetric envelope of the cannula used for either the bandolier or magazine configurations. The volumetric envelope is further increased by the bandolier or magazine, thereby significantly limiting the number of single-use cannulas that can be retained relative to the overall size of the device. Accordingly, a need exists for a storage assembly for an injection device that increases the number of cannulas that can be stored therein.